Risk factors and pattern of metastatic recurrence after endoscopic resection with additional treatment for esophageal cancer

Although esophageal cancers invading the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic resection (ER) are associated with a risk of lymph node metastasis, details of metastatic recurrence after additional treatment remain unknown. We aimed to identify the risk factors for metastatic recurrence and recurrence patterns in patients receiving additional treatment after ER for esophageal cancer. Between 2006 and 2017, patients with pT1a-MM/pT1b-SM esophageal cancer who underwent ER with additional treatment (esophagectomy, chemoradiotherapy [CRT], and radiation therapy) at 21 institutions in Japan were enrolled. We evaluated the risk factors for metastatic recurrence after ER with additional treatment. Subsequently, the rate and pattern (locoregional or distant) of metastatic recurrence were investigated for each additional treatment. Of the 220 patients who received additional treatment, 57, 125, and 38 underwent esophagectomy, CRT, and radiation therapy, respectively. In the multivariate analysis, lymphatic invasion was the sole risk factor for metastatic recurrence after additional treatment (hazard ratio, 3.50; P = 0.029). Although the risk of metastatic recurrence with additional esophagectomy was similar to that with CRT (hazard ratio, 1.01; P = 0.986), the rate of locoregional recurrence tended to be higher with additional esophagectomy (80.0% (4/5) vs. 36.4% (4/11)), leading to a better prognosis in patients with metastatic recurrence after additional esophagectomy than CRT (survival rate, 80.0% (4/5) vs. 9.1% (1/11)). Patients with lymphatic invasion have a high risk of metastatic recurrence after ER with additional treatment for pT1a-MM/pT1b-SM esophageal cancer. Additional esophagectomy may result in a better prognosis after metastatic recurrence.